A meta-analysis of asbestos and lung cancer: is better quality exposure assessment associated with steeper slopes of the exposure-response relationships?

Environ Health Perspect. 2011 Nov;119(11):1547-55. doi: 10.1289/ehp.1002879. Epub 2011 Jun 27.


Background: Asbestos is a well-recognized cause of lung cancer, but there is considerable between-study heterogeneity in the slope of the exposure-response relationship.

Objective: We considered the role of quality of the exposure assessment to potentially explain heterogeneity in exposure-response slope estimates.

Data sources: We searched PubMed MEDLINE (1950-2009) for studies with quantitative estimates of cumulative asbestos exposure and lung cancer mortality and identified 19 original epidemiological studies. One was a population-based case-control study, and the others were industry-based cohort studies.

Data extraction: Cumulative exposure categories and corresponding risks were abstracted. Exposure-response slopes [KL (lung cancer potency factor of asbestos)] were calculated using linear relative risk regression models.

Data synthesis: We assessed the quality of five exposure assessment aspects of each study and conducted random effects univariate and multivariate meta-regressions. Heterogeneity in exposure-response relationships was greater than expected by chance (I2 = 64%). Stratification by exposure assessment characteristics revealed that studies with well-documented exposure assessment, larger contrast in exposure, greater coverage of the exposure history by exposure measurement data, and more complete job histories had higher meta-KL values than did studies without these characteristics. The latter two covariates were most strongly associated with the KL value. Meta-KL values increased when we incrementally restricted analyses to higher-quality studies.

Conclusions: This meta-analysis indicates that studies with higher-quality asbestos exposure assessment yield higher meta-estimates of the lung cancer risk per unit of exposure. Potency differences for predominantly chrysotile versus amphibole asbestos-exposed cohorts become difficult to ascertain when meta-analyses are restricted to studies with fewer exposure assessment limitations.

Publication types

  • Meta-Analysis
  • Review

MeSH terms

  • Asbestos, Amphibole / toxicity*
  • Asbestos, Serpentine / toxicity*
  • Carcinogens, Environmental / toxicity*
  • Case-Control Studies
  • Cohort Studies
  • Lung Neoplasms / chemically induced
  • Lung Neoplasms / epidemiology*
  • Lung Neoplasms / mortality
  • Occupational Exposure*
  • Research Design
  • Risk Assessment


  • Asbestos, Amphibole
  • Asbestos, Serpentine
  • Carcinogens, Environmental